1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * atlas-ezo-sensor.c - Support for Atlas Scientific EZO sensors
4 *
5 * Copyright (C) 2020 Konsulko Group
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7 */
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/delay.h>
12#include <linux/mutex.h>
13#include <linux/err.h>
14#include <linux/i2c.h>
15#include <linux/of_device.h>
16#include <linux/iio/iio.h>
17
18#define ATLAS_EZO_DRV_NAME		"atlas-ezo-sensor"
19#define ATLAS_INT_TIME_IN_MS		950
20#define ATLAS_INT_HUM_TIME_IN_MS	350
21
22enum {
23	ATLAS_CO2_EZO,
24	ATLAS_O2_EZO,
25	ATLAS_HUM_EZO,
26};
27
28struct atlas_ezo_device {
29	const struct iio_chan_spec *channels;
30	int num_channels;
31	int delay;
32};
33
34struct atlas_ezo_data {
35	struct i2c_client *client;
36	struct atlas_ezo_device *chip;
37
38	/* lock to avoid multiple concurrent read calls */
39	struct mutex lock;
40
41	u8 buffer[8];
42};
43
44#define ATLAS_CONCENTRATION_CHANNEL(_modifier) \
45	{ \
46		.type = IIO_CONCENTRATION, \
47		.modified = 1,\
48		.channel2 = _modifier, \
49		.info_mask_separate = \
50			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
51		.scan_index = 0, \
52		.scan_type =  { \
53			.sign = 'u', \
54			.realbits = 32, \
55			.storagebits = 32, \
56			.endianness = IIO_CPU, \
57		}, \
58	}
59
60static const struct iio_chan_spec atlas_co2_ezo_channels[] = {
61	ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_CO2),
62};
63
64static const struct iio_chan_spec atlas_o2_ezo_channels[] = {
65	ATLAS_CONCENTRATION_CHANNEL(IIO_MOD_O2),
66};
67
68static const struct iio_chan_spec atlas_hum_ezo_channels[] = {
69	{
70		.type = IIO_HUMIDITYRELATIVE,
71		.info_mask_separate =
72			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
73		.scan_index = 0,
74		.scan_type =  {
75			.sign = 'u',
76			.realbits = 32,
77			.storagebits = 32,
78			.endianness = IIO_CPU,
79		},
80	},
81};
82
83static struct atlas_ezo_device atlas_ezo_devices[] = {
84	[ATLAS_CO2_EZO] = {
85		.channels = atlas_co2_ezo_channels,
86		.num_channels = 1,
87		.delay = ATLAS_INT_TIME_IN_MS,
88	},
89	[ATLAS_O2_EZO] = {
90		.channels = atlas_o2_ezo_channels,
91		.num_channels = 1,
92		.delay = ATLAS_INT_TIME_IN_MS,
93	},
94	[ATLAS_HUM_EZO] = {
95		.channels = atlas_hum_ezo_channels,
96		.num_channels = 1,
97		.delay = ATLAS_INT_HUM_TIME_IN_MS,
98	},
99};
100
101static void atlas_ezo_sanitize(char *buf)
102{
103	char *ptr = strchr(buf, '.');
104
105	if (!ptr)
106		return;
107
108	memmove(ptr, ptr + 1, strlen(ptr));
109}
110
111static int atlas_ezo_read_raw(struct iio_dev *indio_dev,
112			  struct iio_chan_spec const *chan,
113			  int *val, int *val2, long mask)
114{
115	struct atlas_ezo_data *data = iio_priv(indio_dev);
116	struct i2c_client *client = data->client;
117
118	if (chan->type != IIO_CONCENTRATION)
119		return -EINVAL;
120
121	switch (mask) {
122	case IIO_CHAN_INFO_RAW: {
123		int ret;
124		long tmp;
125
126		mutex_lock(&data->lock);
127
128		tmp = i2c_smbus_write_byte(client, 'R');
129
130		if (tmp < 0) {
131			mutex_unlock(&data->lock);
132			return tmp;
133		}
134
135		msleep(data->chip->delay);
136
137		tmp = i2c_master_recv(client, data->buffer, sizeof(data->buffer));
138
139		if (tmp < 0 || data->buffer[0] != 1) {
140			mutex_unlock(&data->lock);
141			return -EBUSY;
142		}
143
144		/* removing floating point for fixed number representation */
145		atlas_ezo_sanitize(data->buffer + 2);
146
147		ret = kstrtol(data->buffer + 1, 10, &tmp);
148
149		*val = tmp;
150
151		mutex_unlock(&data->lock);
152
153		return ret ? ret : IIO_VAL_INT;
154	}
155	case IIO_CHAN_INFO_SCALE:
156		switch (chan->type) {
157		case IIO_HUMIDITYRELATIVE:
158			*val = 10;
159			return IIO_VAL_INT;
160		case IIO_CONCENTRATION:
161			break;
162		default:
163			return -EINVAL;
164		}
165
166		/* IIO_CONCENTRATION modifiers */
167		switch (chan->channel2) {
168		case IIO_MOD_CO2:
169			*val = 0;
170			*val2 = 100; /* 0.0001 */
171			return IIO_VAL_INT_PLUS_MICRO;
172		case IIO_MOD_O2:
173			*val = 100;
174			return IIO_VAL_INT;
175		}
176		return -EINVAL;
177	}
178
179	return 0;
180}
181
182static const struct iio_info atlas_info = {
183	.read_raw = atlas_ezo_read_raw,
184};
185
186static const struct i2c_device_id atlas_ezo_id[] = {
187	{ "atlas-co2-ezo", ATLAS_CO2_EZO },
188	{ "atlas-o2-ezo", ATLAS_O2_EZO },
189	{ "atlas-hum-ezo", ATLAS_HUM_EZO },
190	{}
191};
192MODULE_DEVICE_TABLE(i2c, atlas_ezo_id);
193
194static const struct of_device_id atlas_ezo_dt_ids[] = {
195	{ .compatible = "atlas,co2-ezo", .data = (void *)ATLAS_CO2_EZO, },
196	{ .compatible = "atlas,o2-ezo", .data = (void *)ATLAS_O2_EZO, },
197	{ .compatible = "atlas,hum-ezo", .data = (void *)ATLAS_HUM_EZO, },
198	{}
199};
200MODULE_DEVICE_TABLE(of, atlas_ezo_dt_ids);
201
202static int atlas_ezo_probe(struct i2c_client *client,
203		       const struct i2c_device_id *id)
204{
205	struct atlas_ezo_data *data;
206	struct atlas_ezo_device *chip;
207	const struct of_device_id *of_id;
208	struct iio_dev *indio_dev;
209
210	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
211	if (!indio_dev)
212		return -ENOMEM;
213
214	of_id = of_match_device(atlas_ezo_dt_ids, &client->dev);
215	if (!of_id)
216		chip = &atlas_ezo_devices[id->driver_data];
217	else
218		chip = &atlas_ezo_devices[(unsigned long)of_id->data];
219
220	indio_dev->info = &atlas_info;
221	indio_dev->name = ATLAS_EZO_DRV_NAME;
222	indio_dev->channels = chip->channels;
223	indio_dev->num_channels = chip->num_channels;
224	indio_dev->modes = INDIO_DIRECT_MODE;
225
226	data = iio_priv(indio_dev);
227	data->client = client;
228	data->chip = chip;
229	mutex_init(&data->lock);
230
231	return devm_iio_device_register(&client->dev, indio_dev);
232};
233
234static struct i2c_driver atlas_ezo_driver = {
235	.driver = {
236		.name	= ATLAS_EZO_DRV_NAME,
237		.of_match_table	= atlas_ezo_dt_ids,
238	},
239	.probe		= atlas_ezo_probe,
240	.id_table	= atlas_ezo_id,
241};
242module_i2c_driver(atlas_ezo_driver);
243
244MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
245MODULE_DESCRIPTION("Atlas Scientific EZO sensors");
246MODULE_LICENSE("GPL");
247